Neurofibromatosis and psychosis: coincidence or co-occurrence?

To the Editor

In the later half of the 20th century, few published case reports addressed the co-occurrence of neurofibromatosis type 1 (NF1) and childhood psychosis. There are contradictory reports in the literature about their association. While a Swedish sample found 6% of children had both psychosis and NF1, a survey in Denmark reported only 0.3% such cases (Gillberg and Forsell, 1984; Mouridsen et al., 1992). No such association or lack of it has been discussed in the medical literature during the past 25 years. Here, we present a case of a boy with NF1 and early psychosis.

A 14-year-old boy of Tongan origin was referred to an early psychosis program in regional Australia. He had been experiencing distressing auditory hallucinations, delusions, disorganized behavior and marked functional decline during the previous 6 weeks. A detailed history indicated no identifiable risk factors for early psychosis. At birth, he was diagnosed as having NF1, and the condition was managed conservatively. Physical examination, biochemistry, serology and thorough organic screening did not reveal any cause for psychosis. Magnetic resonance imaging of the brain showed pre-existing benign hamartomas, unchanged in size from previous scans. An electroencephalography found a mild non-specific increase in slow activity over temporal and parietal regions in line with the NF1 diagnosis. He responded well to low-dose risperidone and gained complete remission of the psychotic symptoms over 12 weeks.

NF1 is a multi-system autosomal dominant disorder that is characterized by cutaneous and skeletal lesions, along with the growth of both benign and malignant nervous system tumors, most notably benign neurofibromas. The clinical issue here is whether the co-occurrence of neurofibromatosis and childhood psychosis might be more than a coincidence. Monoaminergic dysfunction was once postulated as a possible reason for these findings (Gillberg and Forsell, 1984).

The presence of gross pathology in certain areas of the brain or attenuated white matter pathways may be a possible etiology of psychosis. Given considerable advances in knowledge and the application of radiology and genetics in recent decades, attention should be paid to this possible correlation. Any association that is discovered will allow early screening, diagnosis and intervention for high-risk patients.

With our current knowledge, clinicians should be mindful that children diagnosed with NF1 might be at higher risk for developing psychoses later in life. Follow-up longitudinal studies are needed to compare the rates of transition to psychosis in patients with NF1 in comparison with the general population.